Abstract

7Li and11B NMR spectral parameters were obtained for the two structural modifications of lithium metaborate. We first studied the high-temperature γ-form of LiBO2, δiso(11B) ≈ 0, e2qQ/h(11B)=42.5±2.0 kHz, e2qQ/h(7Li)=155±5 kHz. The following values were obtained for monoclinic α-LiBO2 with tricoordination of the boron atom: δiso(11B) = 16±2, e2qQ/h(7Li)=32±10 kHz. The electric field gradient on the7Li and11B nuclei in the different crystal positions was discussed.